S-91274A240 5/16"-18 x 7/8" ASME B18.3, ASTM A574, ASTM B117 Alloy Steel Socket Head Screws

Key Features & Benefits at a Glance

• Exceptional tensile strength of 170,000 PSI provides superior resistance to mechanical failure in demanding applications
• Premium zinc-flake coating delivers outstanding corrosion resistance, extending service life in harsh industrial environments
• Class 3A thread fit ensures precise, secure fastening with minimal play for vibration-resistant assemblies
• High Rockwell C37 hardness maintains structural integrity under heavy loads and repeated use
• 1/4" hex drive design allows for high-torque installation with standard tools while preventing cam-out
• Fully threaded construction enables maximum engagement depth and adjustable positioning flexibility
• Coarse UNC threading facilitates quick assembly and disassembly while resisting clogging in debris-prone environments

Professional Applications & Engineering Value

This zinc-flake-coated alloy steel socket head cap screw addresses critical engineering challenges in heavy machinery, automotive, and industrial equipment applications. The combination of 170,000 PSI tensile strength and Rockwell C37 hardness provides reliable performance in high-stress environments where fastener failure is not an option. The corrosion-resistant zinc-flake coating protects against environmental degradation, making it ideal for outdoor equipment and harsh manufacturing conditions. The 5/16"-18 UNC coarse thread design ensures rapid installation and removal while maintaining secure fastening in vibrating systems. With its fully threaded configuration and 1/4" hex drive, this socket head cap screw delivers consistent clamping force and easy access in confined spaces, reducing assembly time and maintenance costs.

Specification Summary & Compliance

Manufactured to ASME B18.3 specifications with Class 3A thread fit for precision dimensional accuracy. Complies with ASTM A574 material standards and ASTM B117 testing requirements. Meets RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental compliance standards. Features UNC coarse threading with 5/16"-18 thread size and 7/8" length in the inch measurement system.